With a growing popularity of the LCD, the LCD is demanded for better functions.
Referring to FIG. 1, FIG. 1 is a schematic drawing illustrating pixel structures of an LCD panel in the prior art. The LCD panel includes m data lines D″1˜D″m and n scan lines G″1˜G″n. The data lines intersect the scan lines, and two adjacent data lines intersect two adjacent scan lines to define a pixel unit (not labeled). A thin film transistor (TFT) and a liquid crystal capacitor (not shown) are disposed on each pixel unit.
Data signals that are transmitted on the data lines D″1˜D″m can be divided into data signals of positive polarity and data signals of negative polarity reference to a common voltage Vcom which is 0 v. The data signals of positive polarity means that the voltages of data signals are higher than the common voltage Vcom, and the data signals of negative polarity means that the voltages of data signals are lower than the common voltage Vcom. When a data signal of positive polarity and a data signal of negative polarity both have the same gray scale value, theoretically, they have the same display effects.
Liquid crystal molecules have followed common character: when both sides of a liquid crystal layer are applied to electric field and if the direction of the electric field is kept constant for a long time, the characteristics of the liquid crystal molecules are destroyed. That is, the liquid crystal molecules fail to rotate in response to changes of the electric field for forming various gray scales. Therefore, the direction of the electric field has to change every a period of time for reversing the liquid crystal molecules so as to prevent the characteristics of the liquid crystal molecules from being destroyed. There are a variety of driving methods to realize the reversal of the liquid crystal molecules in the LCD field, such as dot inversion, 1+2 dot inversion, column inversion, and row inversion.
When the driving method of the 1+2 dot inversion is employed in the above-mentioned LCD panel, in the case of the pixel units in each row, the direction of the electric field of the liquid crystal capacitance in (4k−3)th and (4k)th columns of the pixel units is opposite to the direction of the electric field of the liquid crystal capacitance in (4k−2)th and (4k−1)th columns of the pixel units. Thus, the polarity of the gray scale voltages of the data lines D″4k−3 and D″4k is opposite to the polarity of the gray scale voltages of the data lines D″4k−2 and D″4k−1, where K is an arbitrary natural number. In addition, the direction of the electric field of the liquid crystal capacitance in odd rows of the pixel units and even rows of the pixel units are opposite. Thus, the voltages of the data lines D″4k−3 and D″4k as well as the data lines D″4k−2 and D″4k−1 have to continuously switch their polarity in a frame time T as shown in FIG. 2. However, the frequent polarity switching must increase power consumption of the LCD panel, resulting in waste of resources.